Multicarrier communications may be described as a communications technique in which multiple carriers or subcarriers are used to communicate information. As an example of multicarrier communications, Orthogonal Frequency Division Multiplexing (OFDM) may be described as a communications technique that divides a communications channel into a number of spaced frequency bands. In OFDM, a subcarrier carrying a portion of the user information may be transmitted in each band. In OFDM, each subcarrier may be orthogonal, differentiating OFDM from the commonly used frequency division multiplexing (FDM). An OFDM symbol may include, for example, a symbol transmitted simultaneously on each of the OFDM subcarriers during the OFDM symbol period. These individual symbols may be referred to as subcarrier symbols.
Some OFDM communication systems may transport payloads or data blocks of varying lengths. In many cases, the end of the transmitted data block may not align with the end of an OFDM symbol, resulting in an unused portion of one or more OFDM symbols. Thus, for example, there may be one or more unmodulated (or unused) subcarriers in the final OFDM symbol for the data block. In many systems, this may be handled by zero-extending the data or repeating the data until the final OFDM symbol is filled. Unfortunately, simply data repeating or zero-extending to fill the OFDM symbol wastes valuable OFDM symbol resources. There may be a need for a technique to make more efficient use of an unused or unmodulated portion of OFDM symbols.